In the past, the application of the usual small annular elastic arch wire supporting ligatures to the orthodontic brackets in the mouth of the patient has been a tedious and time consuming operation. Usually the ligatures are applied by hand and by the use of forceps or similar instruments to stretch the ligatures and to insert the ligatures into the annular support grooves in the brackets. The objective of the present invention is to provide a simple hand tool by which such elastic ligatures may be applied simply and expeditiously in a stretched condition into the annular grooves in the orthodontic brackets and around the arch wire, so that the arch wire may be supported on the brackets.